Question

Sometimes these clouds of dust and gas are so thick that they block out all of the background light. These clouds of dust and gas are called:

a) Hubble Clouds
b) Stellar Clouds
c) Nebulas
d) Dark Nebulas

Answer 1

Dark nebulae are clouds of dust and gas that block out all background light. They can be illuminated by starlight to become reflection nebulae. An example is Barnard 68, a dark nebula that contains tiny solid dust grains.

Step-by-step explanation:

When clouds of dust and gas are so thick that they block out all background light, they are called dark nebulae. These dense clouds, also known as nebulas, are visible because they scatter starlight. They can be illuminated by starlight to become reflection nebulae. An example of a dark nebula is Barnard 68, which contains tiny solid dust grains that block the light of stars behind it.